OVERALL ABSTRACT We will establish a Rheumatic Diseases Research Resource Center at the University of California, San Diego (UCSD). The theme of our Microenvironment in Arthritis Resource MARC (MARC) is to facilitate translational research focused on the joint microenvironment in arthritis. Limited knowledge of in situ joint biology and pathogenic mechanisms in rheumatic diseases has prevented development of novel biomarkers and therapies that target cellular interactions within joint structures. The MARC will address this gap by stimulating interest in the joint microenvironment among a large interdisciplinary group of well-funded scientists from multiple institutions in San Diego. The goal of the MARC is to provide the San Diego scientific community with a comprehensive local framework to plan, perform and analyze a large variety of joint microenvironment studies using invasive and non-invasive technology and foster novel, collaborative, and interdisciplinary arthritis- relevant research. The first two Aims of the Center are to facilitate studies on tissue microenvironment by providing access to (Aim 1) cutting-edge joint imaging technology and approaches to isolate single cells and tissue from joints and to (Aim 2) a dedicated computational service focusing on integration of diverse multi- dimensional datasets. Aim 3 is to lower the barrier for new investigators to enter the field and to foster collaboration between rheumatic disease-focused scientists across San Diego. This will be accomplished via an Enrichment Program, which includes vouchers for core services, pilot and feasibility grant funding, and creation of a new arthritis seminar series and a regional arthritis-focused symposium to stimulate collaboration. The San Diego science community has a deeply rooted combination of creativity, dynamism, collaborative attitude and focus on translation. Thus, our Center will be uniquely positioned to facilitate the novel science that will be transformative for the diagnosis and treatment of rheumatic diseases.